It is well known in the prior art that a tube may be hydroformed to a desired complex tubular shape. The tube is placed between a pair of dies having cavities which define the desired resultant shape of the tube. The ends of the tube are accessible through the die and a seal is connected to the ends of the tube so that pressurized fluid injected into the tube forces the tube to expand and conform to the shape defined by the die cavity. It is also known to mount the dies in a press so that a lower die is stationary on the lower bed of the press and the upper die moves up and down with the upper bed of the press to permit loading and unloading of the tubes from the die.
In order to economically manufacture hydroformed tubes, it would be desirable to provided improvements in the press apparatus by which the tube would be properly held between the dies so that the upper die can be lowered into engagement with the lower die to capture the tube in the cavity defined between the dies. It also is desirable to provide apparatus for mounting the seal on the lower bed of the press in a manner which would facilitate the sealing engagement and subsequent disengagement of the seal from the ends of the tube. Furthermore, it would be desirable to provide effective mechanism for retaining the seal unit in sealing engagement with the ends of the tube against the affects of the high pressure hydraulic fluid acting on the seal in the direction to disengage the seal from the end of the tube.